Give your TRX-4M^™ unstoppable torque with this low-range transmission. The transmission features an ultra-low 40.3:1 reduction ratio for maximum rock-climbing power. Traxxas Pro Built^® transmissions come professionally assembled with bearings and a fresh new Titan^® 180 87-turn motor. There’s no gear mesh to adjust or parts to align. The assembly bolts in as a complete unit for quick and easy installation.